Device for heating and/or vaporizing a fluid such as water

ABSTRACT

A device for heating and/or vaporizing a fluid is provided. The device comprises a heat conductive inner conduit defining a fluid flow pathway. An electrically powered heating element is arranged to surround said inner conduit whereby heat energy from the heating element heats fluid passing through the fluid flow pathway. A casing is provided to sealedly surround the heating element. An exterior surface of the casing is in communication with a space into which heated fluid or vapour is emitted from the outlet of the inner conduit. The casing is heat conductive such that heat energy is received from the heating element heats fluid within said space. Fluid such as water can be efficiently heated by passing it through the fluid flow pathway and having it contact the exterior surface of the casing for double heating. Also, by restricting water flow through the fluid flow pathway can result in easy generation of steam. By having a fluid flow pathway through the heating element, this results in more efficient heating of water and saving in energy. Furthermore, it maintains the operating temperature of the heating element at a lower range thereby the life of the heating element is extended.

TECHNICAL FIELD

The invention relates to a device for heating and/or vaporizing a fluidand particularly, but not exclusively to heating and/or vaporizing amedium such as water.

BACKGROUND ART

Heating water is a daily requirement and there are varied methods ofdoing so. With an accelerated pace of life, the requirements for waterheaters are greater, i.e. there is a requirement for water heaters toheat water to boiling point or above much quicker than current devices.

An existing liquid heater, as shown in FIGS. 1 to 3, comprises a heatconductive tube 3 surrounding a coiled wire heating element 4.Electrical terminals 1 supply electric power to the heating element 4.The heating element terminals 1 are electrically insulated from the tube3 by end caps 2 which also seal the ends of tube 3 from liquid ingress.A heat conducting, but electrically insulating powder 5 fills the spacewithin the tube 3 surrounding the heating element 4. Heating a fluidsuch as water using this device relies on contact of the water with theouter surface of the tube 3. This does not provide rapid transfer ofheat from the heating element 4 to the water. Furthermore, when the userswitches the heater off, an internal core temperature of the heaterremains at a very high level for some time resulting in a shortening ofthe life of the heating element.

Thus, there are a number of disadvantages with the known heater. Onedisadvantage is due to heating only being provided by the outer wall ofthe heater. This leads to user complaints of slowness in heating waterand also leads to energy wastage.

Another disadvantage is due to heating by only the outer heater wall isthat this prevents heat being removed from close to the heating elementwhen power is switched off which results in a shortening of the life ofthe heating element and thus of the heater.

DISCLOSURE OF INVENTION Technical Problem

An object of the invention is to mitigate or obviate to some degree oneor more problems associated with known water heaters.

The above object is met by the combination of features of the mainclaims; the sub-claims disclose further advantageous embodiments of theinvention.

Another object of the invention is to provide a heating device for moreefficiently providing heated water and/or steam.

One skilled in the art will derive from the following description otherobjects of the invention. Therefore, the foregoing statements of objectare not exhaustive and serve merely to illustrate some of the manyobjects of the present invention.

SOLUTION TO PROBLEM Technical Solution

In a first main aspect, the invention provides a device for heatingand/or vaporizing a fluid. The device comprises a heat conductive innerconduit having an interior surface defining a fluid flow pathwaytherethrough and an outlet for emitting heated fluid or vapour from thefluid flow pathway. An electrically powered heating element is arrangednear to an exterior surface of said inner conduit whereby heat energyfrom the heating element is received at the exterior surface of theinner conduit and conducted by the inner conduit to its interior surfaceto heat fluid passing through the fluid flow pathway. A casing maysealably surround the heating element, said casing having an exteriorsurface in communication with a space into which heated fluid or vapouris emitted from the outlet of the inner conduit, said casing being heatconductive such that heat energy received from the heating element isconducted by the casing to its exterior surface to heat fluid withinsaid space.

In a second main aspect, the invention provides a household electricalappliance having a device according to the first main aspect of theinvention.

In a third main aspect, the invention provides a device for heatingand/or vaporizing a fluid. The device comprises an electrically poweredheating element arranged around an inner conduit defining a first fluidflow pathway to heat fluid flowing through said first fluid flowpathway. A housing surrounds the heating element and inner conduit anddefines a second fluid flow pathway arranged to be heated by the heatingelement. An inlet of the second fluid flow pathway is connected to anoutlet of the first fluid flow pathway whereby heated fluid or vapouremitted from the first fluid flow pathway is further heated in thesecond fluid flow pathway.

In a fourth main aspect, the invention provides a household electricalappliance having a device according to the third main aspect of theinvention.

ADVANTAGEOUS EFFECTS OF INVENTION Advantageous Effects

A purpose of the invention is to provide an improved heating device thatcan easily replace a conventional heating device and which provides highenergy conversion efficiency whilst being easy to install andmanufacture.

This purpose is achieved by the invention as defined in the appendedclaims.

The summary of the invention does not necessarily disclose all thefeatures essential for defining the invention; the invention may residein a sub-combination of the disclosed features.

BRIEF DESCRIPTION OF DRAWINGS Description of Drawings

The foregoing and further features of the present invention will beapparent from the following description of preferred embodiments whichare provided by way of example only in connection with the accompanyingfigures, of which:

FIG. 1 is a schematic diagram of a prior art heating tube;

FIG. 2 is a sectional view taken along A-A of FIG. 1;

FIG. 3 is an enlarged view of section B the heating tube of FIG. 1;

FIG. 4 is a schematic diagram of a first embodiment of a heating deviceaccording to the invention;

FIG. 5 is a sectional view taken along A-A of FIG. 4;

FIG. 6 is an enlarged view of section B the heating device of FIG. 4;

FIG. 7 is a perspective view of a heating device according to a secondembodiment of the invention.

FIG. 8 is a sectional view of the heating device of FIG. 7;

FIG. 9 is an exploded view of the components of the heating device ofFIG. 7;

FIG. 10 is a plan view of a heating device according to a thirdembodiment of the invention;

FIG. 11 is a sectional view of the heating device of FIG. 10; and

FIG. 12 is an exploded view of the components of the heating device ofFIG. 11.

MODE FOR THE INVENTION Mode for Invention

The following description is of preferred embodiments by way of exampleonly and without limitation to the combination of features necessary forcarrying the invention into effect.

Reference in this specification to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least one embodimentof the invention. The appearances of the phrase “in one embodiment” invarious places in the specification are not necessarily all referring tothe same embodiment, nor are separate or alternative embodimentsmutually exclusive of other embodiments. Moreover, various features aredescribed which may be exhibited by some embodiments and not by others.Similarly, various requirements are described which may be requirementsfor some embodiments but not other embodiments.

Referring to FIGS. 4 to 6, shown is a first embodiment of a heatingdevice or apparatus according to the invention which is capable ofrapidly heating water to high temperatures and/or of rapidly producingsteam.

The heating device comprises an inner conduit in the form of a centraltube 1, a casing comprising an outer conduit in the form of an outertube 2, an insulating sleeve 3, a heating element in the form of aheating wire 4, an electrical terminal for the heating element in theform of an electrically conducting pipe 5, and an insulating ring 6. Thecentral tube 1 defines a fluid flow pathway through which a fluid suchas water passes to be heated, the tube having an inlet at one end toadmit a fluid and an outlet an its other end to emit a heated fluid orvapour to a space surrounding the heating device. The heating element islocated near to an exterior surface of the central tube 1 to heat it. Ina preferred arrangement, the heating wire 4 comprises a coiled heatingwire which is coiled around the exterior surface of the central tube,but preferably not touching it, particularly where the central tube ismade of a material that is not only heat conductive but electricallyconductive. A magnesium oxide powder layer 7 is provided between theheating wire 4 and the central tube 1 as well as between the heatingwire 4 and the outer tube 2. The powder has electrical insulationproperties as well as thermal insulating properties such that heat fromthe heating wire 4 slowly dissipates through the powder to the centraltube 1 and outer tube 2. The outer tube 2 surrounds the heating wire 4and seals it from ingress of fluid into the space filled by the powder7. Both ends of the heating wire 4 are electrically connected, e.g.welded, to their respective terminal pipes 5 to receive electricalpower. The terminal pipe 5 is electrically insulated from the centraltube 1 by the insulting sleeve 3 and electrically insulated from theouter tube 2 by the insulating ring 6. The insulating sleeve 3 extendsbeyond both ends of the terminal pipe 5 to enhance electricalinsulation. The outer tube 2 has a greater diameter than the centraltube 1 and is arranged coaxially with the central tube 1 to sealablysurround the heating wire 4 arranged around the exterior surface of thecentral tube 1.

In use, when a fluid such as water flows through the central tube 1 itbecomes heated by heat transference from the heating wire 4 to thecentral tube 1 and then to the fluid. Heated fluid emitted from theoutlet of the central tube 1 may be emitted to a space comprising achamber, vessel or receptacle of a household electrical appliance suchas a kettle or steamer or the like. The fluid that is admitted to theinlet of the central tube 1 may comprise already heated fluid from thespace or unheated fluid from another source. In any event, heated fluidor vapour emitted from the central tube 1 into the space is furtherheated by the outer tube 2 through contact with its exterior surface byheat transference from the heating wire 4 to the outer tube 2.

By admitting a fluid to be heated to the fluid flow pathway through thecentral tube 1, this has the advantage of not only increasing heattransference efficiency and thus energy efficiency, but also has theadvantage that heat dissipates more quickly away from the heating wire 4after power is switched off. Furthermore, as heat transferenceefficiency is improved, the heating wire 4 does not reach the excessivetemperatures encountered in the prior art devices and consequently thelife of the heating wire 4 of the present invention is greatly enhanced.

In laboratory measurements, the core temperature of the heating tube wasfound to be 900° C., but the temperature of the tube surface was foundto be 220° C. Because of this improvement, the centre of the centraltube will absorb heat faster and better and transfer this to fluidpassing therethrough very efficiently.

In some embodiments, a pump may be provided to urge fluid to flowthrough the central tube 1. In some embodiments, means may be providedto restrict the amount of fluid admitted to the central tube in orderthat such fluid that is admitted is rapidly heated to at least itsvaporization temperature and is thus emitted from the central tube 1 asa vapour, e.g. as steam.

It will be understood that the shape and configuration of the heatingdevice as described above is not limited to the particular embodimentshown.

Referring now to FIGS. 7 to 9, shown is a second embodiment of a heatingdevice or vaporizer apparatus according to the invention. In thisembodiment, the heating apparatus comprises the heating device of thefirst embodiment of FIGS. 4 to 6 with the addition of a housing 8.Therefore, like numerals to those used in FIGS. 4 to 6 will be used todenote like parts. The housing 8 surrounds the outer tube 2 to define acylindrical annular heating space or chamber 10 around the exteriorsurface of the heating device. As a consequence, the space into whichheated fluid or vapour is emitted from the outlet of the central tube 1of the heating device comprises a space 10 defined by the exteriorsurface of the outer tube 2 and an interior surface of the housing 8sealably surrounding said outer tube 2. The housing 8 has an outlet 11for emitting heated fluid or vapour from said space 10. The housing 8comprises a section of conduit of greater diameter than the outer tube 2which is arranged coaxially with the central tube 1 and outer tube 2.Sealing rings 12 are provided for sealing the ends of the conduit aroundthe outer tube 2. The outlet of the central tube 1 extends to an inletof the housing 8 and may do so by extending interiorly of outer tube 2to the housing 8 or, as shown, exteriorly of both the central tube 1 andthe housing 8 to be connected to said inlet of the housing by anexternal connection pipe 9.

It can be seen that the space or chamber 10 comprises an annularcylindrical chamber surrounding the outer tube 2. Preferably, this isarranged such that a distance from the exterior surface of the outertube 2 to the interior surface of the housing 8 is less than thediameter of the outer tube 2 to provide a shallow chamber 10 for furtherheating of fluid or vapour being emitted from the outlet of the centraltube 1.

In essence, the apparatus of the embodiment of FIGS. 7 to 9 comprisesthe heating wire 4 arranged around the central tube 1 which defines afirst fluid flow pathway to heat fluid flowing through said first fluidflow pathway with the housing 8 surrounding the heating wire 4 andcentral tube 1 (and outer tube 2) and defining a second fluid flowpathway for further heating fluid or vapour emitted from the first fluidflow pathway.

The second fluid flow pathway is oppositely directed to the first fluidflow pathway which is advantageous in that it assists in maintaining aneven heat gradient over the length of the heating wire 4.

In some embodiments, a pump may be provided to force fluid to flowthrough the first and second fluid flow pathways.

In some embodiments, a fluid flow controller may be provided to restrictfluid flow through the first and second fluid flow pathways such thatsaid fluid is vaporized as it passes through said pathways and isemitted as a vapour at the outlet of the second fluid flow pathway, i.e.at the outlet of the housing.

In some embodiments, a space into which heated fluid or vapour isemitted from the outlet of second fluid flow pathway, i.e. from theoutlet of the housing 8, comprises a chamber, vessel or receptacledefined by a household electrical appliance.

In use, when a fluid such as water flows through the central tube 1 itbecomes heated by heat transference from the heating wire 4 to thecentral tube 1 and then to the fluid. Heated fluid or vapour emittedfrom the outlet of the central tube 1 is admitted at the inlet of thehousing 8 to the chamber 10 formed thereby for further heating throughcontact with the exterior surface of the outer tube 2. By making thechamber 10 defined by the housing 8 shallow in depth, i.e. having asmall depth compared to the diameter of the outer tube 2, this greatlyincreased the rapidity with which water flowing through the first andsecond fluid flow passages can be heated to or above boiling point oreven to produce steam.

It will be understood that the shape and configuration of the heatingapparatus as described above is not limited to the particular embodimentshown.

Referring now to FIGS. 10 to 12, this shows another embodiment of aheating apparatus of the type shown by FIGS. 7 to 9 which is also basedon the heating device of FIGS. 4 to 6. In this embodiment, there areprovided two heating devices according to the embodiment of FIGS. 4 to 6arranged within a common housing 8 in a side by side arrangement. Insimilar manner to the embodiment of FIGS. 7 to 9, the housing 8 definesa shallow chamber 10 around the outer tubes 2 of the heating devices.The outlet of each heating device connects to a respective inlet of thehousing 8, but the housing has a single outlet 11 for emitting heatedfluid or vapour to its exterior. Each of the heating devices also has arespective inlet for admitting fluid to their respective central tubes1, but the inlets may be joined by a Y-shaped tubular member 10 forconnection to a single source of incoming fluid.

It will be understood that the shape and configuration of the heatingapparatus as described above is not limited to the particular embodimentshown.

In general, the invention provides a device for heating and/orvaporizing a fluid. The device comprises a heat conductive inner conduitdefining a fluid flow pathway therethrough. An electrically poweredheating element is arranged to surround said inner conduit whereby heatenergy from the heating element heats fluid passing through the fluidflow pathway. A casing is provided to sealably surround the heatingelement. An exterior surface of the casing is in communication with aspace into which heated fluid or vapour is emitted from the outlet ofthe inner conduit. The casing is heat conductive such that heat energyreceived from the heating element heats fluid within said space. Fluidsuch as water can be efficiently heated by passing it through the fluidflow pathway and having it contact the exterior surface of the casingfor double heating. Also, by restricting water flow through the fluidflow pathway can result in easy generation of steam. By having a fluidflow pathway through the heating element, this results in more efficientheating of water and saving in energy. Furthermore, it maintains theoperating temperature of the heating element at a lower range therebyextending the life of the heating element.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly exemplary embodiments have been shown and described and do notlimit the scope of the invention in any manner. It can be appreciatedthat any of the features described herein may be used with anyembodiment. The illustrative embodiments are not exclusive of each otheror of other embodiments not recited herein. Accordingly, the inventionalso provides embodiments that comprise combinations of one or more ofthe illustrative embodiments described above. Modifications andvariations of the invention as herein set forth can be made withoutdeparting from the spirit and scope thereof, and, therefore, only suchlimitations should be imposed as are indicated by the appended claims.

In the claims which follow and in the preceding description of theinvention, except where the context requires otherwise due to expresslanguage or necessary implication, the word “comprise” or variationssuch as “comprises” or “comprising” is used in an inclusive sense, i.e.to specify the presence of the stated features but not to preclude thepresence or addition of further features in various embodiments of theinvention.

It is to be understood that, if any prior art publication is referred toherein, such reference does not constitute an admission that thepublication forms a part of the common general knowledge in the art.

1-37. (canceled)
 38. A device for heating and/or vaporizing a fluidcomprising: a heat conductive inner conduit having an interior surfacedefining a fluid flow pathway therethrough and an outlet for emittingheated fluid or vapour from the fluid flow pathway; an electricallypowered heating element arranged near to an exterior surface of saidinner conduit whereby heat energy from the heating element is receivedat the exterior surface of the inner conduit and conducted by the innerconduit to its interior surface to heat fluid passing through the fluidflow pathway; a casing sealably surrounding the heating element, saidcasing having an exterior surface in communication with a space intowhich heated fluid or vapour is emitted from the outlet of the innerconduit, said casing being heat conductive such that heat energyreceived from the heating element is conducted by the casing to itsexterior surface to heat fluid within said space.
 39. The device ofclaim 38, wherein the heating element comprises a coiled wireelectrically powered heating element which surrounds the exteriorsurface of the heat conductive inner conduit.
 40. The device of claim38, wherein the casing comprises an outer conduit of greater diameterthan the inner conduit and arranged coaxially with the inner conduit tosealably surround the heating element arranged around the exteriorsurface of the inner conduit.
 41. The device of claim 38, wherein theinner conduit has an inlet for admitting fluid to the fluid flowpathway.
 42. The device of claim 41, wherein said inlet of the innerconduit is in communication with the space into which heated fluid orvapour is emitted from the outlet of the inner conduit whereby fluidfrom said space can be readmitted to the fluid flow pathway for furtherheating or vaporization.
 43. The device of claim 42, wherein a fluidflow controller is provided to restrict fluid flow through the inlet tothe fluid flow pathway such that said fluid is vaporized as it passesthrough the fluid flow pathway and is emitted as a vapour at the outletof the inner conduit.
 44. The device of claim 38, wherein said spaceinto which heated fluid or vapour is emitted from the outlet of theinner conduit comprises a space defined by the exterior surface of theouter conduit and an interior surface of a housing sealably surroundingsaid outer conduit, said housing have an outlet for emitting heatedfluid or vapour from said space.
 45. The device of claim 44, whereinsaid housing comprises a third conduit of greater diameter than thecater conduit and arranged coaxially with the inner and outer conduitsto sealably surround the outer conduit.
 46. The device of claim 45,wherein a distance from the exterior surface of the outer conduit to theinterior surface of the housing is less than the diameter of the outerconduit.
 47. A device for heating and/or vaporizing a fluid comprising:an electrically powered heating element arranged around an inner conduitdefining a first fluid flew pathway to heat fluid flowing through saidfirst fluid flow pathway; a housing surrounding the heating element andinner conduit and defining a second fluid flow pathway arranged to foeheated by the heating element, an inlet of the second fluid flow pathwaybeing connected to an cutlet of the first fluid flow pathway wherebyheated fluid or vapour emitted from the first fluid flow pathway isfurther heated in the second fluid flow pathway, wherein the secondfluid flow pathway is oppositely directed to the first fluid flowpathway.
 48. The device of claim 47, wherein the heating elementcomprises a coiled wire electrically powered heating element which iscoiled around the inner conduit to surround the exterior surface of theinner conduit.
 49. The device of claim 47, wherein a casing comprisingan outer conduit of greater diameter than the inner conduit is arrangedcoaxially with the inner conduit to sealably surround the heatingelement arranged around the exterior surface of the inner conduit. 50.The device of claim 47, wherein the inner conduit has an inlet foradmitting fluid to the first fluid flow pathway.
 51. The device of claim50, wherein a fluid flow controller is provided to restrict fluid flowthrough the first and second fluid flow pathways such that said fluid isvaporized as it passes through said pathways is emitted as a vapour atan outlet of the second fluid flow pathway.
 52. The device of claim 47,wherein a space into which heated fluid or vapour is emitted frost theoutlet of second fluid flow pathway comprises a chamber, vessel orreceptacle defined by a household electrical appliance.
 53. The deviceof claim 52, wherein said housing comprises a third conduit of greaterdiameter than the outer conduit and arranged coaxially with the innerand outer conduits to surround the outer conduit.
 54. The device ofclaim 53, wherein the outlet of the first fluid flow pathway extendsexteriorly of both the inner conduit and the housing and is connected tothe inlet of the second fluid flow pathway by an external connectionpipe.
 55. The device of claim 53, wherein said space comprises anannular cylindrical chamber surrounding the outer conduit.
 56. Thedevice of claim 55, wherein a distance from the exterior surface of theouter conduit to the interior surface of the housing is less than thediameter of the outer conduit.
 57. A household electrical appliancehaving a device according to claim 38.